Exemplary embodiments herein relate to automatic vehicle door mirrors. Automatic vehicle door mirrors include a memory mirror controller (“MMC”) that automatically moves a mirror glass as a part of its function. Movement of the mirror glass is controlled by a motor connected to the mirror glass through a gear transmission. If during MMC controlled movement, the mirror glass encounters an obstruction and is blocked from moving, then the motor and gear transmission can slip ratcheting back and forth while making a loud clicking noise. This has been found undesirable by customers.
To limit the motor slip during MMC controlled movement, the MMC continually checks data from a sensor to confirm that the mirror glass is moving toward a target position. If the mirror glass is not moving toward the target position, then the MMC controlled movement is stopped. Due to vehicle voltage and ambient temperatures, motor speeds for the motor in the vehicle mirror can vary widely. To prevent a slow-moving motor from being mis-detected as a slipping motor, the MMC waits for a predetermined period of time during which slip detection is prohibited. During the slip protection prohibition time, if the mirror glass is blocked from moving and is being driven by a fast moving motor, slipping will occur and the customer may hear several loud undesirable clicks. On the other hand, if the mirror glass is being driven by a slow moving motor, the MMC may mistakenly conclude, based on the data received from the sensor, that the mirror is blocked, and therefore stop delivery of electrical power to the motor before the motor reaches the target position.